I think e-mail, i.e., the software, is "decentralised" if one is willing to break conventions and standards applying to how it is used. The way email software is used today is of course highly centralised, for various reasons. However the option of using email software to administer email in a decentralised way, i.e., going against standards and conventions, is not a topic one ever sees discussed.
With every item of software, there was a time before the standards and conventions existed. The software still works without the standards and conventions. Someone had to test it before those "rules" were established.
But an "email industry" has arisen, and a ridiculous number of individuals and organisations choose to depend on mostly unregulated third party "email providers". When people encourage others to follow conventions and standards, such as using third party email providers, e.g., because it's easy, and others follow these suggestions, a decentralised solution can effectively become centralised.
Is an e-mail provider required in order to run a Mastodon server.
https://docs.joinmastodon.org/user/run-your-own
I think e-mail, i.e., the software, is "decentralised" if one is willing to break conventions and standards applying to how it is used. The way email software is used today is of course highly centralised, for various reasons. However the option of using email software to administer email in a decentralised way, i.e., going against standards and conventions, is not a topic one ever sees discussed.
With every item of software, there was a time before the standards and conventions existed. The software still works without the standards and conventions. Someone had to test it before those "rules" were established.
But an "email industry" has arisen, and a ridiculous number of individuals and organisations choose to depend on mostly unregulated third party "email providers". When people encourage others to follow conventions and standards, such as using third party email providers, e.g., because it's easy, and others follow these suggestions, a decentralised solution can effectively become centralised.